Molnár V. et al.: The reproductive success of Hungarian orchids has not changed in the last century - 1097 - NO EVIDENCE FOR HISTORICAL DECLINES IN POLLINATION SUCCESS IN HUNGARIAN ORCHIDS MOLNÁR V., A. 1* ‒ LÖKI, V. 1 ‒ TAKÁCS, A.1 ‒ SCHMIDT, J.2 ‒ TÖKÖLYI, J.2 ‒ BÓDIS, J.3 ‒ SRAMKÓ, G.1, 3 1 Department of Botany, University of Debrecen, Egyetem tér 1., H-4032, Debrecen, Hungary, (phone: +36-52-512-900 / 62648; fax: +36-52-512-943) 2MTA-DE Lendület’ Behavioural Ecology Research Group, Department of Evolutionary Zoology, University of Debrecen, Egyetem tér 1., H–4032 Debrecen, Hungary, (phone: +36-52-512-900 / 62331; fax: +36-52-512-941) 3Department of Plant Sciences and Biotechnology, University of Pannonia, Georgikon Faculty, H-8360 Keszthely, Festetics u. 7., Hungary, (phone: +36-83-545-095; fax: +36-83-545-058); 4MTA-ELTE-MTM Ecology Research Group, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary (phone: +36-52-512-900 / 62632; fax: +36-52-512-943) *Corresponding author e-mail: [email protected] (Received 3rd Feb 2015; accepted 11th Mar 2015) Abstract. Pollination crisis (the decline of pollinator populations) is a global phenomenon which threatens biodiversity, human welfare and economy. The degree to which different plant populations/species are affected by pollination crisis is still unclear. In this study, long-term herbarium dataset was used to quantify the reproduction rate of Hungarian orchids between 1853 and 2008. We quantified fruit-set rate of 663 specimens belonging to 27 species. Data were available from an average of 10.3±9.3 localities, 76.5±43.2 years, and 23.4±25.6 specimens per species. Herbarium data were validated with field-observed data in case of the different pollination strategies. According to our results, the reproductive success of the vast majority of orchid species has not changed during time and pollination crisis is not apparent in Hungary at least until the end of the 20th century. Keywords: herbaria, natural history collections, Orchidaceae, pollination crisis, pollination mode Introduction Pollinators provide key ecosystem services in most terrestrial ecosystems (Chee, 2004; Boyd and Banzhaf, 2007; Wallace, 2007; Fisher and Turner, 2008). Their activity is crucially important in the long-term survival of indigenous plant communities (Ashman et al., 2004; Aguilar et al., 2006) and the productivity of cultivated plants (Klein et al., 2007; Ricketts et al., 2008). For most crop plants and wild plants (particularly in the temperate climate zones) the most important pollinators are insects, especially bees, which are declining parallel to insect-pollinated plants at global (Kearns et al., 1998; Potts et al., 2010) and western European (Biesmeijer et al., 2006) scale. The main causes of the observed global pollination crisis have not been fully identified, but are potentially connected to the fragmentation and destruction of (semi-) APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 13(4): 1097-1108. http://www.aloki.hu ● ISSN 1589 1623 (Print) ● ISSN 1785 0037 (Online) DOI: 10.15666/aeer/1304_10971108 2015, ALÖKI Kft., Budapest, Hungary Molnár V. et al.: The reproductive success of Hungarian orchids has not changed in the last century - 1098 - natural habitats, spread of parasites, the use of chemicals in agriculture and global climate change. From this point of view, the recent and well documented climate change (Parmesan and Yohe, 2003; Root et al., 2003; Schröter et al., 2005; IPCC, 2007) deserves particular attention. Phenological shifts linked to changing climatic conditions were documented in different groups of plants (Fitter and Fitter, 2002; Parmesan, 2006; Post et al., 2008), including orchids (Robbirt et al., 2011; Molnár V. et al., 2012b). So far, little is known about climatic responsiveness of orchid-pollinators, but pollination mode was found to be the most important predictor of phenological response of central European terrestrial orchids (Molnár V. et al. 2012b). Nevertheless, any phenological mismatch between pollinators and flowering plants may substantially reduce the reproductive success of plants through decreased pollination efficiency (Fitter and Fitter, 2002; Hegland et al., 2009; Bartomeus et al., 2011; Rafferty and Ives, 2011). European terrestrial orchids represent an ideal research object for studying temporal changes in pollination efficiency for several reasons. First, since agamospermy (asexual seed production) is very rare in the family (Nygren, 1967; Catling and Catling, 1991), the presence of a fruit is almost always an indication of successful pollination (Neiland and Wilcock, 1995). Second, individual reproductive success of orchids is easy to estimate by counting the flowers and fruits on the shoot (Neiland and Wilcock, 1998). Third, orchids exhibit diverse pollination modes (self-pollinating, nectar-rewarding, food- and sexual deception (Dafni, 1984; Jersáková et al., 2006), consequently, their dependence on the abundance and diversity of pollinating insects differs between species. Fourth, different orchid species are attractive for specific group of insects, such as bees and wasps (Hymenoptera), butterflies (Lepidoptera) and beetles (Coleoptera) (Claessens and Kleynen, 2011). Our aims in this study were (1) to characterize Hungarian orchid species in terms of reproductive success based on herbarium records, (2) determine the effect of pollination mode on fertilization success and (3) evaluate historical changes in reproductive success in orchids during the past decades. Our predictions were the following: the reproductive success of autogamous species is temporarly invariable and relatively high (since they do not depend on pollinators), the reproductive success of entomophilous species depends on pollination mode: nectar- rewarding species show higher fructification rate than deceptive taxa, the reproductive success of entomophilous species (both nectar rewarding and deceptive) is decreasing due to the decline of pollinator populations. Natural history collections contain important and useful information on the reproductive success of orchids in historical context (Farrell, 1985; Pauw and Hawkins, 2011). To test our hypotheses we collected data on fructification rate from all publicly accessible Hungarian herbaria and analyzed these with respect to pollination mode and time of collection. Materials and methods Quantifying fruit-set We used the most widely utilised (and the easiest) method of measuring of reproductive success in orchids: quantifying fruit-set (Neiland and Wilcock, 1998). The Herbarium Database of Hungarian Orchids, compiled recently (Molnár V. et al., 2012a) allowed us to analyse reproductive success of 681 specimens belonging to 27 species based on a historical dataset which spans 155 years (Table 1). APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 13(4): 1097-1108. http://www.aloki.hu ● ISSN 1589 1623 (Print) ● ISSN 1785 0037 (Online) DOI: 10.15666/aeer/1304_10971108 2015, ALÖKI Kft., Budapest, Hungary Molnár V. et al.: The reproductive success of Hungarian orchids has not changed in the last century - 1099 - Table 1. List of the species and characterization of the dataset used in this study. Abbreviations: A - autogamous, FD – food deceptive, NR – nectar rewarding. Date of collection Pollination No. of No. of Species Duration mode localities Median±SD specimens (years) Anacamptis coriophora NR 11 1944±17 55 33 Anacamptis morio FD 7 1945±26 73 15 Anacamptis palustris FD 4 1944±52 106 7 Anacamptis FD 14 1956±40 134 27 pyramidalis Cephalanthera A 31 1946±32 132 71 damasonium Cephalanthera FD 23 1939±26 104 30 longifolia Cephalanthera rubra FD 9 1954.5±12 29 16 Cypripedium calceolus FD 3 1939.5±13 27 6 Dactylorhiza incarnata FD 19 1948±29 126 24 Dactylorhiza viridis NR 7 1947±11 25 17 Epipactis atrorubens NR 8 1919±21 61 24 Epipactis helleborine NR 9 1926±19 71 17 Epipactis microphylla A 22 1937±36 149 71 Epipactis palustris A 16 1937±31 112 48 Epipactis purpurata NR 11 1952±22 77 24 Epipactis tallosii A 3 1948±38 66 6 Goodyera repens NR 2 1954±1 2 6 Gymnadenia conopsea NR 5 1922±39 106 7 Gymnadenia NR 2 1904±55 95 8 odoratissima Limodorum abortivum A 14 1952±30 93 26 Liparis loeselii A 2 1969±16 38 10 Neottia ovata A 12 1949.5±34 134 16 Neottia A 38 1950±29 121 119 nidus-avis Orchis militaris FD 13 1951±31 91 59 Orchis purpurea FD 5 1942±31 77 6 Orchis simia FD 2 1961±42 60 9 Platanthera bifolia NR 25 1946±32 137 31 We considered only intact herbarium specimens collected in fruiting stage (Fig. 1). The number of flowers (both fertilized and non-fertilized) and the number of fruits were counted on each specimen collected at fruiting stage and identified at species level. For statistical analyzes we used only species for which at least 3 herbarium records were collected. In the whole dataset the mean±SD numbers of records / species were 23.4±25.6, which were collected from 10.3±9.3 localities, during 76.5±43.2 years. Life-history characterisation Species were categorized into three groups according to their pollination mode – autogamy (including obligate and facultative self-pollination), nectar-rewarding entomophily and food deceptive entomophily, following Molnár V. et al. (2012b). A full list of all investigated species, as well as the sequence data used for phylogenetic reconstruction, is given in Table 1. APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 13(4): 1097-1108. http://www.aloki.hu ● ISSN 1589 1623 (Print) ● ISSN 1785 0037 (Online) DOI: 10.15666/aeer/1304_10971108 2015, ALÖKI Kft., Budapest, Hungary Molnár V. et al.: The reproductive success of Hungarian orchids has not changed in the last century - 1100 - Figure 1. Orchis militaris sheet from the collection of the Department of Botany at the University of Debrecen (DE), collected near to Dabas on the 23th of May in 1951, by Tibor Simon and Olga Borsos. Its four fruits are well identifiable. Statistical analyses To analyze historical changes in reproductive success and its relationship to pollination mode, we used generalized linear mixed models (GLMMs). Since fruit-set is proportion data following a binomial distribution, we used binomial GLMMs with the number of fruits (successes) and number of unpollinated flowers (failures) as a bivariate response.